I have a question that I could not think through. While multiple qemu/kvm processes are running at the same time, how to prevent one guest from using others' TLB? For all the guests have the same TID=0 for userspace and TID=1 for kernel. > -----Original Message----- > From: kvm-ppc-owner@xxxxxxxxxxxxxxx > [mailto:kvm-ppc-owner@xxxxxxxxxxxxxxx] On Behalf Of Hollis Blanchard > Sent: Saturday, July 26, 2008 2:55 AM > To: avi@xxxxxxxxxxxx > Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx > Subject: [PATCH 5 of 5] kvm: powerpc: Map guest userspace > with TID=0 mappings > > # HG changeset patch > # User Hollis Blanchard <hollisb@xxxxxxxxxx> # Date > 1217011852 18000 # Node ID 080b9c9515a5593babc8cac73687b053d7d3f124 > # Parent c832dfc7a6b50ace3c37d00b16ef9f5b46284b3e > kvm: powerpc: Map guest userspace with TID=0 mappings. > > When we use TID=N userspace mappings, we must ensure that > kernel mappings have been destroyed when entering userspace. > Using TID=1/TID=0 for kernel/user mappings and running > userspace with PID=0 means that userspace can't access the > kernel mappings, but the kernel can directly access userspace. > > The net is that we don't need to flush the TLB on privilege > switches, but we do on guest context switches (which are far > more infrequent). Guest boot time performance improvement: about 30%. > > Signed-off-by: Hollis Blanchard <hollisb@xxxxxxxxxx> > > --- > 7 files changed, 40 insertions(+), 18 deletions(-) > arch/powerpc/kernel/asm-offsets.c | 2 - > arch/powerpc/kvm/44x_tlb.c | 37 > ++++++++++++++++++++--------------- > arch/powerpc/kvm/booke_guest.c | 2 + > arch/powerpc/kvm/booke_interrupts.S | 2 - > arch/powerpc/kvm/emulate.c | 2 - > include/asm-powerpc/kvm_host.h | 4 +++ > include/asm-powerpc/kvm_ppc.h | 9 ++++++++ > -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
